How GoodDayTo judges stargazing weather
For stargazing, daytime sunshine is irrelevant; what matters is the night sky. GoodDayTo combines the upcoming weather with astronomical darkness and moon context, so a clear but bright moonlit or twilight hour is treated differently from a truly dark clear window.
- Astronomical darkness
- Moon illumination
- Moonrise / moonset
- Cloud cover
- Precipitation
- Wind
🌞 Make the most of the good window
- Travel away from city lights when practical and safe.
- Allow your eyes time to adapt to darkness.
- The live score now includes moon brightness and true astronomical darkness. Local light pollution and atmospheric seeing are still outside the score and are not guessed.
What makes the best stargazing window
A clear sky is necessary but not always sufficient. GoodDayTo combines cloud and precipitation with true astronomical darkness and moon context. A bright moon above the horizon can wash out faint galaxies and nebulae even when the sky is cloudless, while the same night may become much better after moonset. That is why the tool searches upcoming hours rather than judging the whole night from sunset conditions.
If you are observing the Moon, planets or bright star clusters, you may personally accept a moonlit window that scores lower for deep-sky observing. Give your eyes time to adapt to darkness and, where practical, move away from direct street lighting.
What the stargazing score cannot know
GoodDayTo does not currently measure local light pollution, atmospheric seeing, haze transparency, smoke, nearby obstructions or whether clouds are concentrated on the particular part of the sky you want to observe. Astronomy data and weather forecasts can identify a promising window, but a quick visual sky check at the location is still valuable before travelling far.
What the score means
GO means the weather signals we can measure look favourable. WAIT means conditions are mixed and a better hour may be nearby. NOT TODAY means the forecast currently contains enough unfavourable signals that this activity is unlikely to be a good weather choice. These are planning recommendations, not safety clearances.
Frequently asked questions
Does the score include moon phase?
Yes. When astronomy data is available, the live score uses moon phase, illumination, moonrise/moonset and astronomical twilight together with the weather forecast.
Why is cloud cover so important?
Cloud directly obscures the sky, so it is one of the strongest weather signals for visual stargazing.
Can I use it for astrophotography?
It is a useful first weather screen, but serious astrophotography also depends on moonlight, seeing, transparency, target position and equipment.